Textile drafting mechanism



June 4, 1963 R. HUBER A|51- AI 3,091,814

TEXTILE DRAF TING MECHANISM Filed March 20, 1958 3 Sheets-Sheet 1 ATTYS.

June 4, 1963 R. HUBER ET AI.

TEXTILE DRAFTING IIEcIIIINIsI/I 3 Sheets-Sheet 2 Filed March 20, 1958INVENTORSI RICHARD HUBI-:R FRIEDRICH KBLER Bv im ATTYS.

June 4, 1963 R. HUBER ETAI 3,091,814 TEXTILE DRAFTING MECHANISM FiledMarch 20, 1958 3 Sheets-Sheet 3 INVENTORS RICHARD HI'JBER FRIEDRICHKUBLER ATT YS.

United States Patent Ciice 3\,9l,8l4 Patented .lune 4, 1963 3,91,814TEXTLE DRAFTM G MEQHANlSM Richard Huber, Stuttgart-Nord, and FriedrichKhler, Stuttgart-Bad Cannstatt, Germany, assignors to SKFKugellagerfabriken Gesellschaft mit hesehrankter Haftung, Schweinfurt,Germany, a corporation of Germany Filed Mar. 20, 1958, Ser. No. 722,673Claims priority, application Germany Mar. 29, 1957 13 Claims. (Cl.19-28i) This invention is for improvements in or relating to textiledrafting mechanism and is concerned with mechanism having a pivotallymounted top-roll carrier arm which can be locked, in the operatingposition, to a station-ary part of the machine and which receives toprolls on guide arms which are adapted for lateral swinging on the toprolls.

For the faultless operation of a drafting mechanism, it is necessary forthe axes of the top rolls to be parallel to those of the bottom rollsduring operation. For this reason, constructions have been designedwherein the twin top rolls are mounted in guide arms received forlateral swinging movement in the top-roll carrier arm, so that they canautomatically align themselves parallel to the bottom rolls duringoperation. The biasing or weighting of the top rolls is effected, inthese constructions, by helical springs which bear at one end on theguide arm and at the other end lagainst a fixed abutment in the toprollcarrier arm. Although helical springs have proved satisfactory inpractice as weighting means yfor top rolls at low weighting pressures,they have the disadvantage that, in addition to forces acting in thedirection of their central longitudinal axis, laterally acting forcesalso arise which, particularly at high pressures, assume a value whichcounteracts an accurate self-alignment of the guide arms or of the twintop rolls parallel to the bottom rolls. As a result, there isinterference with the advantageous results intended to be obtained bythe provision for lateral swinging of the guide arms in the top-rollcarrier arm or this lateral swinging may be entirely prevented if veryin quality of the yarn produced.

In order to overcome this disadvantage, it has been proposed that thesprings should Ibe tested for the direction of their aforesaid lateralforces before being installed in the drafting mechanism, and should beinstalled in the drafting mechanism in such a setting that the saidlateral forces operate in a neutral direction, that is to saylongitudinally of the top-roll carrier arm. In this manner, the actionof the lateral forces was rendered comparatively harmless. However, thetesting of each individual spring which was necessary, and the carefulinstallation thereof in the drafting mechanism, involved considerableexpenditure of time and labor and hence corresponding high costs.

In drafting mechanisms in which very high weighting pressures arerequired, one helical spring is often not sufficient as a weightingmeans, so that a plurality of weighting springs have to be installed,connected one behind the other, for example. As a result of the adoptionof this construction the lateral forces of the springs are apt to assumetoo high a value, and in addition, a clumsy arrangeon which rest theweighting means acting.

ment of the elements of the drafting mechanism is involved. In manycases, moreover, the space necessary for the installation of additionalweighting springs is not available inside the drafting mechanism.However, it is impossible to obtain a very high weighting pressure on aguide arm with only one single helical spring because this would have tobe of a comparatively stijf construction or would reach dimensions whichwould make it unsuitable for installation in a drafting mechanism. Aparticular disadvantage of stiff helical springs, apart from acorrespending increase in the lateral force, is the relatively steepspring characteristic. This means that in the event of the guide armcarrying the top rolls swinging down to the plane of the drafting fieldto differing extents, there is a marked variation in the pressure actingon the corresponding top rolls. In practice, however, such variabledownward swinging cannot 'be avoided because the roll covers arereground at intervals and become smaller in diameter as a result, sothat the guide arm swings further down `and the spring exerts aconsiderably reduced pressure on the top rolls in accordance with theaforesaid steep characteristic. On the other hand, there would be acorresponding increase in pressure if the spring force were adapted toan laverage roll diameter and a top roll of maximum diameter were used.Such variations in weighting pressure, combination with the inaccurateparallel alignment of the `axes of the top rolls with those of thebottom rolls, caused by the aforesaid lateral forces of the springs,lead to uneven and faulty yarn when the drafting mechanism is inoperation.

It is an object of the present invention to overcome these disadvantagesand to provide a drafting mechanism wherein the transmission of highpressures to the top rolls is -assured without adversely affecting theirsatisfactory self-alignment parallel with the bottom rolls, and whereindespite defection of rolls, during operation, a substantially constantpressure is assured. According to the invention, this object is achievedby arranging that `the weighting means allocated to the guide arm aremounted, together with their seatings, for lateral swinging movement,and that the guide arms are supported with point or line contact by tworetaining members arranged inside the top-roll carrier arm. By theadoption of this arrangement, the adverse effect of the aforesaidlateral forces of the springs is eliminated in a reliable manner duringthe operation of the drafting mechanism, while the aforesaid lateralswinging movement takes place in directions parallel to the plane of thedrafting iield b arm for lateral swingthe guide ar-m carrying the toptance between the top rolls can easily be varied by adjusting members.The stirrups may, like the guide arm, be manufactured in a simple mannerfrom sheet metal so that the seatings for the weighting means, whichmay, for example, take the form of helical springs, can be mpresseddirectly in the guide arms.

The retaining members may be two in number, one 'located above the otherand the guide arms may be bent into substantially right angled formationwith one portion engaging at its end around the upper retaining memberafter the fashion of half a bush, and being supported against the lowerretaining member either directly or through an interposed additionalmember. As mentioned above, the retaining members are preferably in theform of pins. These may advantageously be arranged with theirlongitudinal axes parallel to the aries of the top rolls and be providedwith bearing surfaces lfor the guide arms or for the holders carryingthe guide arms. For example, the bearing surfaces may be constituted bythe cylindrical surfaces of the pins or may consist fof circumferentialgrooves in which correspondingly shaped ribs on the guide arms orholders engage. Such'ribs may alternatively rest on the cylindricalsurface :of the pins. In either case, it is advisable to select thedimensions in such a manner that only a point Y or line Contact isobtained on the pins as a result of whichl there is practically nofriction which might hamper satisfactory self-alignment of the guidearms.

It is also contemplated, in carrying out the present invention that theguide arm may be formed of resi-lient material through tension in whichthe top rolls are biased or weighted, and, if desired, an additionalweighting spring may be allocated to one or more guide arms in a carrierarm. 'The weighting pressures may be considerably increased by theinstallation of an additional weighting spring, the characteristic curveof which is comparatively gradual so that, in the event of a variationin the distance which the guide arm swings downwardly carrying the toprolls towards the corresponding bottom rolls, no variation in weightingpressure takesplace or only a slight variation which is insignificant inpractice.

The additional fweighting spring aforesaid may take the form of a leafspring and may be bent at an angle and mounted inside the guide arm, andprovided with Vguide means, for example an impressed trough, whichengages over a correspondingly formed guide, for example a rib, in theguide arm. The angular additional weighting spring may, with advantage,be supported at each end on portions 'of the guide arm.

The additional weighting spring may also take the form of a helicalspring, one end ci which bears on one portion of the guide arm, whileits other end bears on a support carried on the other portion of theguide arm. The said support may either be integral with the guide armlor be mounted thereon as an added member as desired. The latteralternative enables the guide arms to be modiiied in a simple manner toreceive additional weighting springs as a result of which, as mentionedabove, a considerable increase is immediately possible in the weightingpressures acting on particular top rolls, while retaining a gradualcharacteristic curve iorrthe spring.

According to the invention, the downward swing of the guide arms may belimited by stops, and the stops may consist, for example, of contactlugs or the like connected to the guide arm and, if a holder is used, ofan abutment mounted on an associated particular holder. it is furtheradvisable to construct the stops in the form of anchors with supporting'tabs against which the guide arms bear to limit their downward swing.Loops or rings may also serveras stops, which at one end engage under ahump yon the guide arm and at the other end are received in a guide in astationary part of the drafting mechanism, for example the stirrup orholder. A further construction or the stops is one in which lugs arebent out or the guide arm, and rest against angled portions of thetop-roll carrier arm. Alternatively, angled portions may be bent inwardsfrom the top-roll carrier arm to limit the downward movement of theguide arm.

Embodiments of the invention are illustrated by way yof example in thedrawings. In these drawings:

FlGURE 1 shows a top-roll carrier and weighting arm in elevation,partially in section;

FIGURE 2 shows a somewhat modified construction of a tcp-roll carrie-rarm, in elevation and partially in section;

FlGURE 3 shows a section on the line -lII-TII in FIGUR-E 2;

FIG-URE 4 shows ano-ther modified construction of a top roll carrierarm, in longitudinal section;

FIGURE 5 shows a section lon the line V-V in FIG- URE 4;

FIGURE. 6 shows a further embodiment ot the carrier arm in longitudinalsection;

FGURE 7 shows a section on the line VII- VII in FlGURE 6;

FIGURE 8 shows a single guide with FiGURE 6, in plan view;

FGURE 9 shows a further embodiment of the carrier arm, partially inlongitudinal section;

FIGURE l() shows a section on the 'line 'URE 9;

FIGURE ll shows a plan view of a guide arm with an additionalsupportingportion, in accordance with FIG- URE 9.

Referring -iirstl'yV to FiGURE l, a top-roll carrier arm 2, which isbent substantially into the form of a U in cross-section, is pivotallymounted on a supporting bar l lined to the machine and is held in theoperating position by means of a locking device. This locking device isnot shown in FlGUlE l but may be similar to Athe device shown at 103 inFiGURE 2 lwhich cc-operates with a stationary part or vthe machine,Received inside the arm Z tor longitudinal adjustment therealong arestirrups 4 and 74 with downwardly bent arms, which can be located byscrews o reaching through a slot 5 in the arm 2. The stirrup 4 shown inFIGURE 1 at the side remote from the'supporting bar l comprisesretaining members constructed in the form of pivot pins 7 and '77 aroundwhich are received pin-engaging means or tongues 8 o1' 'l on a holder 9.The holder 9 carries, on angled arms 9', a pivot pin 1? for the pivotalreception ot a substantially angle-shaped guide or support arm 1l, thelower` end of which is constructed in a manner known per se with asaddle-shaped support l2 to receive a pair of top rol-ls i3 indicated inchain line in the drawing (see FIG. 5). A seating 14 to 4receive one endof bias means in the formof a helical spring 15 is impressed in theupper end of the guide arm il. The other end of the helical spring i5rests against a seating 14 pressed out of the holder 9. The holder 9*and the guide arm `11 constitute an articulated guide-arm assemblyhaving entirely self-contained bias means in the form of the spring l5,urging the support portion l2 downwardly to press the roll i3 againstthe roll 16. f,

A contact lug .1S provided on angled webs in the guide arm il bearsagainst an abutment 17 on the arm 9 of the holder 9 and thus limits theswing 4of the guide arm il about the pivot 1d.

The lholder and therefore the entire guide-arm assembly can also swinglaterally parallel to the plane of the drafting field, to accommodatewhich movement the tongue S comprises a pressed out rib which isreceived in a circumferential `recess in the pivot pin 7. The tongue 78cooperates with the pin 77 in like manner. In this manner, the twin toprol-l 13, which rests as usual, on the bottom roll 16, indicated inchain line in the drawing, can automatically align itself, bringing itsaxis parallel tothe axis of the bottom roll. The spring ll', with itsseatings 14 and i4', also swings about the pivotV provided by the ribs.

arm in accordance X-X in FIG- In the embodiment illustrated in FIGURE l,the two stirrups 74 most adjacent to the support bar 1, comprise pivotpins 19 on which the guide or support arms 11 are mounted for pivotingonly. The weighting or biasing of each of these guide arms r11 islikewise affected by bias means in the form of helical springs 15 eachof which rests on the one hand against a seating pressed out of theguide arm 11' and on the other hand against a seating pressed out of thestirrup 74. A limitation of the swing of the guide arms 11 is obtainedby means of parts 35 bent out of the guide arms, bearing againstcorresponding abutment surfaces on the stinrup 74. The slot 5 and thelixing screws 6 for the stirrups 4 and 74 are covered by a hood which ispivotally mounted on the arm 2, thus preventing the penetration of ulfinto the interior of the arm 2.

In the embodiment shown in FIGURES 2 and 3, an arm 102 similar to thearm 2 receives pivot pins 22 and 122 for the direct reception of aholder 21. The holder 21 comprises pin-engaging means in the form ofbearing tongues 23 and 123 with impressed ribs which engage in recessesin the pins and permit a lateral swinging movement of the holder 21parallel to the plane ofthe drafting lield (see particularly rib 23 andrecess 24 in the pin 22 in FIG. 3). At its front end, the lholder 21 isextended and provided with an impressed seating 26 to receive bias meansin the form of a helical spring 25, the other end of which rests againsta seating 26 in the glide or support arm 28 which is received forpivoting about a pin 27 mounted in the holder 21. The holder 21 furthercomprises at its lower end, hook-shaped Contact lugs 29 which engageunder a web 30 constructed in the form of an abutment face on the guidearm 2S and thus limit the swing of the guide arm 28 after the release ofthe arm 11.22 by the locking device 103. The guide arm 28 is constructedat its lower end with a saddle-shaped support 31 which carries the twintop roll 13. The holder 21, the guide arm 2S and the spring constitutean articulated guide arm assembly having entirely self-contained biasmeans and yoperable to swing laterally on the pins 22 and 122 parallelto the plane of the drafting eld.

The two guide or support arms 28 adjacent to the supporting lbar 1 areeach pivoted on a pin 32 in a holder 33 which is held againstdisplacement in the arm 102, for example by a screw 6 in a slot 5. Eachhelical spring 25 (only one is shown) rests against seatings pressed outof the guide arm 28 and the holder 33. A limitation of the swing of theguide arm 28' (FIGURE 2) is effected by means of parts 34 bent out ofthe holder 33 (FIGURE 3) against which the guide arm 2S' bears. The modeof operation of the holder of FIGURE 2 corresponds with that o-f the oneshown in FIGURE l, though no provision is made for longitudinaladjustment of the holder 21 in the arm 192.

In FIGURES 4 and 5 of the drawing there is shown a top-roll carrier arm202 which is bent substantially into a U-shape and is closed at its twoends. The arm 202 is secured by means of a bracket 1', indicated inchain line in the drawing, to the supporting bar 1 which is xed to themachine and likewise indicated in chain line. At the top, the arm 202comprises slots or bores 5 through which screws 6 reach to secure thestirrups 84 and 35 in place. As in the other embodiments, these areprovided with downwardly bent arms and are longitudinally adjustablealong the arm 262 according to the length of the slots 5. Mountedbetween the downwardly bent arms of the stirrups 84 and 85 are the pivotpins 87 and 8S to receive double-armed guide arms 35 and 35 of resilientmaterial which serves as the biasing means. One arm of the guide arms 35and 35 is arranged between the arms of the stim'up 84 and is constructedwith a pin-engaging tongue in the form of half a bush at its free upperend so that it engages partly around the upper pin 87, The guide armmerely rests against the lower pin 88 of the stirrup 84. In order toreduce the friction between the upper pivot pins 87 and the guide arms35 and 35', the latter have ribs 35 pressed 'out which rest with pointor line contact on the pins 87. Similar ribs are provided at 36' toengage the pin 88, so that the arms 35 and 35', as can be seen fromFIGURE 5, can swing laterally in the direction of the arrow A parallelto the plane of the drafting field. In its front end, each of the guidearms 35 and 35 comprises a saddle-shaped support y112 to receive thetwin top rolls 13, which are indicated in chain line and whichco-Joperate with bottom rolls 16, likewise illustrated in chain line. Inorder to limit the swinging of the lower arm of the guide arms 35 and35', holding the twin top rolls 13, a guide, in the form of a slot, isprovided at 37 in the stirrup 84 and at `37 in the stirrups 85 toreceive a loop or ring 39 or 39 which reaches under a hump 38 bent outof the guide ar The length of the guides 37 and 37 should be such that,when the arm 202 is swung down towards the bottom rolls 16, the 'toprolls 13 are raised so far that the loops 39 and 39l are above thebottom end yof the guideways 37 and 37 and when the arm 2112 is lockedin operative position (see FIGURE 4) the top rolls exert the pre-setpressure on the bottom rolls 15. As a result `of the resilientconstruction of the guide arms 35 and 35', a little or no variationbiasing pressure occurs when the top rolls 13 are displacedperpendicular to the plane of the drafting held, because the springcharacteristic curve is very gradual even at high pressures. Theresilient guide arms `35 and 35 and the associated saddleshaped supports112 comprise guide arm assemblies having entirely self-contained biasmeans and operable to swing laterally on the pins 37 and 88 parallel tothe plane of the drafting field.

Should a considerable increase in the pressure be necessary in such adrafting mechanism, then, as can be seen rom FIGURE 4, an additionalbias in the form of a leaf spring 4)y bent at an angle is interposedbetween the lower pin S3 an-d the guide arm 35. This additional spring40 is provided, in the region of the lower pin 88, with a stamped touttrough 41 with which it engages over the corresponding rib 36 in theguide arm 35 and rests with point lor line contact on the pin S3. As aresult, a considerable increase in pressure is rendered possible whileretaining a perfect ability for the whole guide arm 35 to swinglaterally, without the springs characteristic curve becoming steeper.

In order to secure the guide arms 35 and 35 inside the stirrups 84 andS5, tongues 42 are pressed out of the latter so that the portion of eachguide arm 35 and 35 lying between the two pins 87 and `38 is limited astoits downward or oounterclockwise swinging movement.

Referring now to FIGURES 6 8 of the drawing, it will be seen that ahelical spring 43 may also be used as additional biasing spring, whichrests with one end on the free resilient arm of the guide arm l carryingthe twin top roll 13 and with the other end on a supporting member 44 onthe guide arm 135. This supporting member 44 is preferably made integralwith the guide arm y135 and constructed at its front end in the form ofa spring retainer 44 to receive the upper end of the helical spring 43.To limit the swinging Iof the lower arms of the guide arms 135 carryingthe top rolls 13 outwardly bent lugs 45 are provided thereon (seeparticularly FIGURE 7) to bea-r against inwardly bent portion 46 of thearm 212. The mounting Aof the guide arms 135 inside the stirrup 214 andthe securing of the stirrups inside the top-roll carrier and weightingarm 212 is effected in the same manner as in the embodiment shown inFIGURE 4. The guide arms i135 and their associated saddle-shapedsupports comprise guide arm assemblies having entirely selfcontainedbias means and operable to swing laterally on the pins of the stirrups214 in the plane of the drafting eld.

Finally, FIGURES 9-1-1 show a further embodiment of a resilient guidearm with an additional biasing spring. In the guide arm 235, which isillustrated in the drawing at the front end of the a-rm 222, thesupporting portion 144, which forms a spring retainer 144 for thehelical spring 143, is integral with the guide arm 235. In contrast tothe embodiments shown in FIGURES 1 to 8, an anchor 147, which reachesthrough slots or perforations in the guide arm 235 and the supportingportion i144, is provided for limiting the swinging movement of theguide arm 235 about the pivot. At its ends, the anchor 147 is 'providedwith bent or twisted tabs 148 and 148 (see particularly FIGURE 10) whicheffect the said limitation by bearing against the edges of the slots inthe guide arm 235 and supporting portion 144. The guide arm 235, thesupport portion 144, the spring '143, the anchor 147 and thesaddle-shaped supports comprise a guide arm assembly having entirelyself-contained biasmeans and operable to swing laterally on the pins ofthe carrier arm 222 in the plane of the drafting field.

ln the middle guide arm 335 shown in FIGURE 9, the supporting portion 49is constructed in the form of an additional part and is substantiallyU-shaped, and -rails Sil bent out of the arms of the supporting portion49 bear from the rea-r against the part of the guide arm 335 lyingbetween the pivots 171 and 172, while a web 51, which joins the two armsof the supporting portion 49, has its end face, which is curved towardsthe pin 171, in edge contact with the upper portion of the guide arm335. The web 51 lies in a plane passing through the centre axis of theupper pivot 17-1 so that the additional helical spring only acts on thelower arm of the guide arm 335.

The spring -143 bears at one end on the lower end of the guide arm 335and at the other end on a seating on the supporting portion 49. As inthe foremost guide arm illustrated in FIGURE 9, the swinging movement islimited by an anchor 247 with bent or twisted tabs. The guide arm 335,the support portion 49', the spring and anchor 247, and thesaddle-shaped supports comprise a guide arm assembly having entirelyself-contained bias means and operable to swing laterally on the pins ofthe carrier arm 222 in the plane of the drafting field.

The arm 222 may be held in the operating position by means of a lockingdevice 53 (see FIGURE 9) which is known per se, and is actuated by meansof an operating lever 52. The arm 222 is released from the operatingposition by pivoting the lever 52 counteroloclcwise on its pivot topermit the depending linli of the locking device 53 to move downwardlyso that it may be disengaged from the hook-shaped part which is mountedon the apparatus which carries the lower rolls 16. The length of theoperating lever permits the upper rolls to be forced against the lowerrolls with a very high loading pressure. After the locking device hasbeen released, it can be swung up and if necessary secured to its upperposition. Similar devices are shown in FIGS. 4 and 6. In FIGS. 2. and 3,the locking device 1t3 may be lreleased for displacement out of hookingengagement with a retainer similar to that shown in FIG. 9. To this end,the operating Alever is displaced 180 counterclockwise until it abutsthe free end of the arm 102. Further downward pressure on the leverforces the upper rolls 13 downwardly against the lower rol-ls .16 withsuthcient pressure to unhook the device 103 and permit it to be pivotedout of the path of the retainer, for example by the part projectingupwardly above the pinned connection to the operating lever and arm 102.Thereupon, the carrier arm 102 may be pivoted upwardly on the bar 1.

In order to limit the swinging of the guide arms 235 and 335 towards therear, tongues 142 may -be pressed out of the stirrups and rest eitherdirectly against the port-ion `of the guide arm lying betwen the pins asshown with arm 235 or, if the supporting portion 49 separate from theguide arm 335 is used, against the rail 50 (FIGURE 9).

The middle stirrup and the one adjacent to the bracket may be adjustablein the slot in the arm 22,2, as a result of which the mutual distancebetween the top yrolls 13 may be varied. A further stirrup may also bereceived inside the arrn 222, depending on the length of the slot andthe practical requirements.

It is to be understood that the invention is not restricted to theprecise constructional details set forth.

Y We claim:

l. Textile drafting lmechanism comprising a series of top and bottomrolls defining therebetween a drafting field, a top roll carrier arm,pin means rigidly mounted in said carrier arm, |and a guide arm assemblyfor one top roll having at one end portion pin-engaging means mounted onsaid pin means and supporting said guide arm assembly for lateralswinging movement parallel to said drafting field and restricting saidpin-engaging means against pivotal movement on said pin meansperpendicular to said drafting field, said guide arm assembly includingtop roll supports at the-opposite end portion thereof mounted 'forswinging movement relative to said pinengaging means perpendicular tosaid drafting field to displace the top roll into and out of engagementwith .the associated bottom roll, and said guide arm assembly includingentirely self-contained bias means to urge said top roll supports towardthe associated bottom roll.

2. Textile drafting mechanism according to claim l including stop meansfor limiting displacement by said bias irneans of said guide armassembly adjacent said top roll supports.

3. Textile drafting mechanism according to claim l wherein said pinmeans comprises a pair of spaced -pins disposed substantially parallelto the roll axes of said top and bottom rolls, and having their axesaligned in a plane transverse to the drafting field, said pin-engagingmeans comprising at least one tongue wrapped around said pin means andhaving at least one impressed rib engaging said pin -means to allordsaid :lateral swinging movement parallel to said drafting eld.

4. Textile drafting mechanism according to claim 1 including a stirrupadjustably mounted on -said carrier arm and mounting said pin meanstherein for adjustment longitudinally of said carrier ar-m.

5. Textile drafting mechanism according to claim 1 wherein said biasmeans comprises a substantially flat resilient arm portion mounting saidpin-engaging means at one end position and said top supports at theopposite end portion.

6. Textile drafting mechanism according to claim 5, including means forlimiting the flexure of said resilient arm portion.

7. Textile drafting mechanism according to claim 5, including a springelement, a first seat for said spring element on said guide arm assemblyadjacent said pin-engaging means and an opposed seat for said springclement on said resilient arm portion adjacent said top roll supports.

8. Textile drafting mechanism according to claim 7 wherein said springconsists of a leaf spring element.

9. Textile drafting mechanism according to claim 7 `wherein said springconsists of a helical spring element.

10. Textile drafting mechanism according to claim 9, wherein said firstseat comprises a rigid arm projecting outwardly lfrom said guide armassembly adjacent said pin-engaging elements to ovcrlie said resilientarm, said helical spring being compressed between said rigid arm andsaid resilient arm to supplement the bias of said resilient arm. Y

ll. Textile drafting mechanism according to claim l wherein said lguidearm assembly comprises a holder having said pin-engaging means thereon,and a support arm pivotally mounted on said holder for pivotal movementabout an axis parallel to said top roll and mounting said top rollsupports thereon, said bias means being conlined under stress betweensaid holder and said support arm.

l2. Textile drafting mechanism according to claim 11 wherein said biasmeansV comprises a helical spring seated at one end on said holder andat the other end on said support arm to bias `said Itop roll supportstoward the associated bottom roll.

13. Textile drafting mechanism according to claim 1 wherein the guidearm assembly comprises relatively movable parts, said pin-engagingelements being mounted on one of said parts and said top` roll supportsbeing mounted on another of said parts, said bias means being confinedunder stress between said parts.

UNITED STATES PATENTS Hohloch Apr. 20, 1954 Da-usch Nov. 6, 1954 DauschJune 26, 1956 Anderson Aug. 14, 1956 Dausch Jan. 14, 1958 FOREIGNPATENTS Switzerland Jan. 16, 1954

1. TEXTILE DRAFTING MECHANISM COMPRISING A SERIES OF TOP AND BOTTOMROLLS DEFINING THEREBETWEEN A DRAFTING FIELD, A TOP ROLL CARRIER ARM,PIN MEANS RIGIDLY MOUNTED IN SAID CARRIER ARM, AND A GUIDE ARM ASSEMNBLYFOR ONE TOP ROLL HAVING AT ONE END PORTION PIN-ENGAGING MEANS MOUNTED ONSAID PIN MEANS AND SUPPORTING SAID GUIDE ARM ASSEMBLY FOR LATERALSWINGING MOVEMENT PARALLEL TO SAID DRAFTING FIELD AND RESTRICTING SAIDPIN-ENGAGING MEANS AGAINST PIVOTAL MOVEMENT ON SAID PIN MEANSPERPENDICULAR TO SAID DRAFTING FIELD, SAID GUIDE ARM ASSEMBLY INCLUDINGTOP ROLL SUPPORTS AT THE OPPOSITE END PORTION THEREOF MOUNTED FORSWINGING MOVEMENT RELATIVE TO SAID PINENGAGING MEANS PERPENDICULAR TOSAID DRAFTING FIELD TO DISPLACE THE TOP ROLL INTO AND OUT OF ENGAGEMENTWITH THE ASSOCIATED BOTTOM ROLL, AND SAID GUIDE ARMS ASSEMBLY INCLUDINGENTIRELY SELF-CONTAINED BIAS MEANS TO URGE SAID TOP ROLL SUPPORTS TOWARDTHE ASSOCIATED BOTTOM ROLL.